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The number of glyphosate intoxication cases has been increased after the regulation of paraquat. Unfortunately, there are no reports on the potential concentration of glyphosate for those acute intoxicated patients admitted to emergency rooms and the correlation between the concentration of glyphosate and clinical symptoms in Korea up to our knowledge. As a nonselective herbicide, analysis of glyphosate requires derivatization because of its amphoteric and strongly polar nature. In order to develop a method to determine the concentration of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA) in blood samples without derivatization, liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was utilized with a hydrophilic interaction chromatography (HILIC) column. The validation of this method showed that the limits of detection (LODs) and limits of quantitation (LOQs) for glyphosate and AMPA were 50 and 100ng/mL, respectively. In addition, matrix effect, recovery rate, and accuracy and precision in intra and inter-day were evaluated during the validation study of this method. Blood samples acquired from five glyphosate intoxicated patients were analyzed to investigate the correlation between the concentration of glyphosate and clinical symptoms. These patients were previously admitted to the emergency room at a University Hospital in Korea after glyphosate was self-administered in suicide attempts or by accident. As results of blood sample study, the concentration of glyphosate and AMPA were found in the range of 1.0-171.1 and 0.2-2.6μg/mL, respectively. The concentration ratio of glyphosate to AMPA was 55-71. According to the clinical reports for those patients, they were in the age between 47 and 82 years old and administered about 50-400mL. The blood samples were collected within 2-5h after administration of glyphosate. Among the intoxicated patients, the most common clinical symptom was metabolic acidosis, identified in four patients. The comparison between the concentration of glyphosate and administered dosage did not show the correlation, which suggests further investigation on the effects of surfactants in glyphosate from different vendors. [ABSTRACT FROM AUTHOR]

Homovanillic acid (HVA) and vanillylmandelic acid (VMA) are end-stage metabolites of catecholamine and are clinical biomarkers for the diagnosis of neuroblastoma. For the first time in Korea, we implemented and validated a liquid chromatography tandem mass spectrometry (LC–MS/MS) assay to measure urinary concentrations of HVA and VMA according to Clinical and Laboratory Standards Institute guidelines. Our LC–MS/MS assay with minimal sample preparation was validated for linearity, lower limit of detection (LOD), lower limit of quantification (LLOQ), precision, accuracy, extraction recovery, carryover, matrix effect, and method comparison. A total of 1209 measurements was performed to measure HVA and VMA in spot urine between October 2019 and September 2020. The relationship between the two urinary markers, HVA and VMA, was analyzed and exhibited high agreement (89.1% agreement, kappa's k = 0.6) and a strong correlation (Pearson's r = 0.73). To our knowledge, this is the first study to utilize LC–MS/MS for simultaneous quantitation of spot urinary HVA and VMA and analyze the clinical application of both markers on a large scale for neuroblastoma patients. [ABSTRACT FROM AUTHOR]